1. Technical Field
The present invention relates to a projector that projects an image formed of a virtually increased number of pixels based on pixel shift.
2. Related Art
There is a known projector that uses a technology for virtually increasing the number of pixels based on a birefringence phenomenon. For example, there is a known projector to which an optical path modulation unit is added (see JP-A-2003-5132). The optical path modulation unit includes a polarization modulation device that switches the polarization state of light passing therethrough by turning on and off a power supply and a birefringence plate that based on birefringence transmits a specific polarization component by spatially modulating (shifting) the optical path thereof and transmits other polarization components without modulating (shifting) the optical paths thereof. The projector can display an image formed of pixels the number of which is twice as many as a standard number by synchronizing the switching operation of the polarization modulation device provided in the optical path modulation unit with the display timing of an image display device.
In a mechanism in which optical path modulation causes pixel shift as illustrated by the optical path modulation unit in JP-A-2003-5132, however, when part of the light is reflected and returns to the image display device or any other component where an image is formed, the part of light forms a light component traveling in an unintended direction (light component traveling toward image light projection side, for example), contributing to ghost light generation, a decrease in ANSI contrast, and other types of degradation in image quality.